This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.

What is it?

Under normal conditions, DDT is found as white crystals or powder which have a very faint smell. DDT is very stable and evaporates fairly easily. It does not dissolve in water, but dissolves very well in fats.

What is it used for?

At the time of the second world war, DDT was widely used as an insecticide - particularly against insects spreading malaria. Up until the 1970s, DDT was used extensively as a pesticide. Since then, its use has been banned in the UK and EU. Today, it is still used in some developing countries.

Where does it come from?

New releases of DDT occur during its manufacture, tranportation, storage and use as a pesticide. Releases to soil can evaporate into the atmosphere or run off into water bodies. There are not thought to be any natural sources of DDT to the environment.

How might it affect the environment?

DDT is very toxic to wildlife, particularly to aquatic organisms and birds. Most worringly it has been observed to interefere with the breeding of rare birds of prey, by thinning the shells of their eggs. It can also cause gender defects and alter gender ratios in populations. The fact that DDT dissolves well in fats and is very stable means that it concentrates through the food chain. It is also highly persistent in the environment - and is therefore classed as a persistent organic pollutant (POP). The negative effects of DDT pollution appear to extend to a global as well as local level.

How might exposure to it affect human health?

Dichlorodiphenyltrichloroethane (DDT) can enter the body either by inhalation of air contaminated with dichlorodiphenyltrichloroethane, ingestion of contaminated food or dermal contact with dichlorodiphenyltrichloroethane. Exposure to dichlorodiphenyltrichloroethane mainly occurs by ingestion of contaminated food. Inhalation of dichlorodiphenyltrichloroethane can affect the central nervous system and may result in a range of adverse health effects including headache, nausea, dizziness, vomiting, tremors and seizures. Ingestion of large amounts of dichlorodiphenyltrichloroethane can cause nausea, vomiting, diarrhoea and effect similar to those for ingestion. Dermal contact with dichlorodiphenyltrichloroethane may cause dermal irritation. Exposure to large quantities can result in health effects similar to those for inhalation and ingestion. Nursing infants can be exposed to dichlorodiphenyltrichloroethane from breast milk if the mother has been exposed to dichlorodiphenyltrichloroethane. It is not known whether the effects of exposure in children differ from adults. The International Agency for Research on Cancer has designated dichlorodiphenyltrichloroethane as a possible carcinogen. However, exposure to dichlorodiphenyltrichloroethane at normal background levels is unlikely to have any adverse effect on human health.

What steps are being taken to limit the potential impacts?

DDT is listed as a UK Red List pollutant, signifying that its presence in the environment is of particular concern. Releases of DDT are controlled through the Food and Environmental Protection Act (FEPA 1985), the Control of Pesticides Regulations (COPR 1986) and the UK Surface Waters (Dangerous Substances) Regulations (SI 1997/2560). It is not listed for authorised use as a pesticide in the UK (including Scotland) in the Pesticide Safety Directorate. It is also regulated through the European Directive concerned with pollution of the aquatic environment (76/464/EEC) and that which restricts the marketing and use of certain dangerous substances (76/769/EEC). Its use as a pesticide is now banned in many countries. International levels are controlled through the UNECE POPs Protocol and it is listed as a candidate substance under the Helsinki and OSPAR Conventions which protect the marine environments of the Baltic Sea and north-east Atlantic Ocean respectively.